/*
 Copyright  2002-2007 MySQL AB, 2008 Sun Microsystems
 All rights reserved. Use is subject to license terms.

  The MySQL Connector/J is licensed under the terms of the GPL,
  like most MySQL Connectors. There are special exceptions to the
  terms and conditions of the GPL as it is applied to this software,
  see the FLOSS License Exception available on mysql.com.

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; version 2 of the
  License.

  This program is distributed in the hope that it will be useful,  
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  02110-1301 USA

 */

package com.mysql.jdbc;

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.SQLClientInfoException;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;

/**
 * An implementation of JDBC4ClientInfoProvider that exposes
 * the client info as a comment prepended to all statements issued
 * by the driver.
 * 
 * Client information is <i>never</i> read from the server with this
 * implementation, it is always cached locally.
 * 
 * @version $Id: $
 */

public class JDBC4CommentClientInfoProvider implements JDBC4ClientInfoProvider {
	private Properties clientInfo;
	
	public synchronized void initialize(java.sql.Connection conn,
			Properties configurationProps) throws SQLException {
		this.clientInfo = new Properties();
	}

	public synchronized void destroy() throws SQLException {
		this.clientInfo = null;
	}

	public synchronized Properties getClientInfo(java.sql.Connection conn)
			throws SQLException {
		return this.clientInfo;
	}

	public synchronized String getClientInfo(java.sql.Connection conn,
			String name) throws SQLException {
		return this.clientInfo.getProperty(name);
	}

	public synchronized void setClientInfo(java.sql.Connection conn,
			Properties properties) throws SQLClientInfoException {
		this.clientInfo = new Properties();
		
		Enumeration propNames = properties.propertyNames();
		
		while (propNames.hasMoreElements()) {
			String name = (String)propNames.nextElement();
			
			this.clientInfo.put(name, properties.getProperty(name));
		}
		
		setComment(conn);
	}

	public synchronized void setClientInfo(java.sql.Connection conn,
			String name, String value) throws SQLClientInfoException {
		this.clientInfo.setProperty(name, value);
		setComment(conn);
	}
	
	private synchronized void setComment(java.sql.Connection conn) {
		StringBuffer commentBuf = new StringBuffer();
		Iterator elements = this.clientInfo.entrySet().iterator();
		
		while (elements.hasNext()) {
			if (commentBuf.length() > 0) {
				commentBuf.append(", ");
			}
			
			Map.Entry entry = (Map.Entry)elements.next();
			commentBuf.append("" + entry.getKey());
			commentBuf.append("=");
			commentBuf.append("" + entry.getValue());
		}
		
		((com.mysql.jdbc.Connection)conn).setStatementComment(
				commentBuf.toString());
	}
}